In the related art, as a commonly and widely known connector (for example, an SMA connector), there is a screw-type connector in which a male-side connector and a female-side connector are connected through screwing together. As illustrated in FIG. 13A, a connector 100 includes a male-side connector 101 and a female-side connector 110. A screw thread 111a is formed on an outer circumferential surface of an end portion 111 of the female-side connector 110, and a screw thread 102a corresponding to the screw thread 111a of the female-side connector 110 is formed on an inner circumferential surface of a coupling nut 102 of the male-side connector 101. The coupling nut 102 is rotatable and has a hexagon nut shape. The male-side connector 101 and the female-side connector 110 are connected to each other such that a pin 103 of the male-side connector 101 is inserted into a pin hole 112 of the female-side connector 110 during connection. Then, the coupling nut 102 is tightened up, thereby screwing the screw thread 102a and 111a of the male-side connector 101 and the female-side connector 110, respectively, and connecting both of the connectors 101 and 110. However, in the connector 100, it is necessary to perform screw tightening (screw loosening in a case of disconnecting) whenever connection is performed. Therefore, problems arise in that screw tightening work is complicated and work efficiency is degraded.
By comparison, in order to cope with the complicated screwing of the connector described above, a so-called push-on type connector (hereinafter, referred to as a “push-on connector”) in which, the screw tightening work described above is omitted and engagement with the female-side connector is performed through one touch is known (see Patent Document 1). According to this document, a coupling inner circumferential portion positioned on an inner circumferential surface of an end portion of the female-side connector engages with, from inside, an elastic bulge portion on an elastic outer circumferential wall provided on a male-side connector. In this manner, the male-side connector and the female-side connector are fitted-connected to each other. As described above, the male-side connector and the female-side connector are connected by only the engagement of the elastic bulge portion described above.
Further, there is also another example in the related art in which a screw thread portion of a common female-side connector is subjected to machining (see Patent Document 2). According to the connector, the screw thread in the related art is not provided, but a protrusion is provided on an outer circumferential surface of the female-side connector, and the protrusion is caused to engage with a corresponding inclined long hole of a male-side connector. In this manner, bayonet locking-type attachment and detachment are performed.